Property dealer blackmailing original papers for more commission

I have purchased a house in Sector-16 Faridabad from a seller staying in Delhi.My property agent in between was Mr. Wadhwa, c/o Wdhawa Properties, Sector 16, Faridabad. The documentation help required at the court for registry was given Mr. Raj Kumar Verma (Document Writer) in Faridabad Court- RKV. Registry has completed. Now as a next step, I need to apply for the transfer of this property in HUDA on my name.For this, a bunch of documentation needs to be signed by the seller, which was already taken at the time of registry. Without my consent MY dealer(wadhwa) has taken all these papers from the document writer (RKV) and is now black mailing me that I need to pay him the commission of 1%, else he is not going to give back the documents signed by the seller. In a requesting manner, I have asked him to take 0.5 %, which was the agreement before we initiate the property search. I do have the phone audio recordings with me, for all these discussions. I don't even know, if he is a registered dealer and paying tax also or not.Please help me in this case.